The traditional three piece railway freight truck consists of one bolster and two side frames that are configured to utilize friction shoes between the bolster and side frames as a means to provide damping of the suspension. The friction shoes additionally provide a limited means to keep the relationship of the side frames aligned squarely to the bolster and wheelsets. Lateral track displacement irregularities are transmitted to the wheelsets and into the side frames creating uneven lateral displacement of the side frames. The uneven displacement of the side frames exceeds the friction shoes' squaring capability, allowing the side frames to pivot or hinge about the friction shoes and bolster. The pivoting or hinging of the side frames yaws the wheelsets, creating misalignment to the railway track, which limits the stability of the traditional three piece freight truck. Further, the parallelograming of the side frames to the bolsters and wheelset is referred to as wrapping. The wrapping of the truck creates misalignment to the railway track, which limits the stability of the three piece truck.
The present invention relates to enhancing the stability of the three piece truck by adding a transom between the side frames. The pivotal, but rigid attachment of the transom to side frames provides warp stiffness between the side frames to prevent parallelograming of the side frames to the bolsters and wheelset, which in turn keeps the truck aligned to the railway track. The transom connects to the side frames in a manner that it can be attached to existing or to new three piece trucks. The rigid pivotal connection of the side frames to transom allows for longitudinal rotation. The longitudinal rotation in parallel with the track, such that truck side frames attached to the wheelsets adjust to track cross level height and irregularities without affecting the warp stiffness of the truck.
The stabilized railway freight car truck bolster is supported on springs. The springs are supported on the transom which is pivotally supported on the side frames.
It is an object of the present invention to provide a railway freight car truck having improved stability and resistance to misalignment with the track.